Journal of Biomaterials and Nanobiotechnology, 2011, 2, 90-96 doi:10.4236/jbnb.2011.21012 Published Online January 2011 (http://www.SciRP.org/journal/jbnb) Copyright © 2011 SciRes. JBNB Assembly of Oligoglycine Layers on Mica Surface* Svetlana V. Tsygankova 1 , Alexander A. Chinarev 1 , Alexander B. Tuzikov 1 , Ilya S. Zaitsev 1 , Nikolai Severin 2 , Alexey A. Kalachev 3 , Jurgen P. Rabe 2 , Nicolai V. Bovin 1* 1 Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia; 2 Department of Physics, Humboldt University Berlin, Berlin, Germany; 3 Plasmachem GmbH, Berlin, Germany. Email: bovin@carb.ibch.ru Received October 7 th , 2010; revised November 10 th , 2010; accepted December 20 th , 2010. ABSTRACT Assembly of [Gly 7 -NHCH 2 -] 4 C, [Gly 7 -NHCH 2 -] 3 C CH 3 and [Gly 4 NH(CH 2 ) 5 -] 2 peptides on mica surface in aqueous so- lution was studied. The peptides are capable of forming atomically smooth (2.65-4.3 nm in height) layers assembled as polyglycine II. Monomers in the layers are situated normally to the surface. Formation of analogous flat 2D structures also takes place in solution but much more slowly than on mica surface, i.e. negatively charged surface plays an active role promoting the assembly. Keywords: Self-Assembling, Oligoglycine, Scanning Force Microscopy, Monolayers 1. Introduction Self-assembly of small molecules on solid surface is an attractive way for fabrication of advanced materials and nano-devices [1]. Basically, self-assembled monolayers (SAMs) constructed on gold from functionalized long-chain hydrocarbon thiols [2] are used for this pur- pose. Such SAMs, held primarily due to Van der Waals interaction, are rather soft architectures precisely repro- ducing imperfect curvature of the surface-template. In contrast, peptides are capable of forming rigid architec- tures due to multiple and highly narrowed hydrogen bonds [3]. This property is intrinsic i.e. generally it does not depend on the template. In polyglycine II structure, parallel peptide chains are arranged as 3 1 helix forming a net of hydrogen bonds (all CO and NH groups are in- volved) [4-6]; this package is rigid and thus especially attractive for design of new flat layers and for smooth- ening of other rough surfaces. Canonical polyglycine II is formed by a long-chain polymer Gly n in a solid phase [4]; earlier, we have demonstrated that short oligoglycines with n = 7 are capable of forming the polyglycine II ar- chitecture if four chains are organized in a star-like manner [6]. Such symmetrical tetraantennary peptide [Gly 7 -NHCH 2 ] 4 C forms platelet-like 2D supramolecular assemblies (hereinafter referred as tectomers), which are proved to be stable not only in solid phase but also in aqueous solutions. In the both cases Raman spectra of tectomers have a band pattern consistent to that of crys- talline polyglycine II. We analyzed conceivable ways of [Gly 7 -NHCH 2 ] 4 C packaging in tectomers and choose the model, in which [Gly 7 -NHCH 2 ] 4 C monomers with paired antennae in polyglycine II conformation are situated normally to the tectomer plane. Thickness of this model structure is in the best agreement to thickness of tectom- ers measured by scanning force microscopy (SFM), 4.5 nm [6]. Later we showed that tectomers can be formed on a surface more readily than in solution volume, par- ticularly on mica due to the opposite charges of terminal NH 2 groups and mica surface [7]. The current paper de- scribes the assembly of tetra-, tri-, and biantennary oli- goglycine peptides (Scheme 1) on mica surface more closely and demonstrates that the assembly leads to atomically smooth and durable mono- or bi-layers (Scheme 2). Also we describe the application of scan- ning force microscopy for investigation of sur- face-promoted assembling of the antennary designed oligoglycines. Tectomers are attractive material for na- notechnologies, because they can serve as a platform for fabrication of nano devices, as well as for smoothing, strengthening, and functionalization of rough surfaces, and for encapsulation of micro-objects [8]. 2. Experimental Peptides [Gly 7 -NHCH 2 -] 4 C, [Gly 7 -NHCH 2 -] 3 CCH 3 , and [Gly 4 -NH(CH 2 ) 5 -] 2 (Scheme 1) were synthesized by ac- tivated esters method in solution, by stepwise elongation * The work was supported by the Program “Molecular and cell biol- ogy”, from the Presidium of the Russian Academy of Sciences.